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1/*
2 * Alarmtimer interface
3 *
4 * This interface provides a timer which is similarto hrtimers,
5 * but triggers a RTC alarm if the box is suspend.
6 *
7 * This interface is influenced by the Android RTC Alarm timer
8 * interface.
9 *
10 * Copyright (C) 2010 IBM Corperation
11 *
12 * Author: John Stultz <john.stultz@linaro.org>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 */
18#include <linux/time.h>
19#include <linux/hrtimer.h>
20#include <linux/timerqueue.h>
21#include <linux/rtc.h>
22#include <linux/alarmtimer.h>
23#include <linux/mutex.h>
24#include <linux/platform_device.h>
25#include <linux/posix-timers.h>
26#include <linux/workqueue.h>
27#include <linux/freezer.h>
28
29/**
30 * struct alarm_base - Alarm timer bases
31 * @lock: Lock for syncrhonized access to the base
32 * @timerqueue: Timerqueue head managing the list of events
33 * @timer: hrtimer used to schedule events while running
34 * @gettime: Function to read the time correlating to the base
35 * @base_clockid: clockid for the base
36 */
37static struct alarm_base {
38 spinlock_t lock;
39 struct timerqueue_head timerqueue;
40 struct hrtimer timer;
41 ktime_t (*gettime)(void);
42 clockid_t base_clockid;
43} alarm_bases[ALARM_NUMTYPE];
44
45/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
46static ktime_t freezer_delta;
47static DEFINE_SPINLOCK(freezer_delta_lock);
48
49#ifdef CONFIG_RTC_CLASS
50/* rtc timer and device for setting alarm wakeups at suspend */
51static struct rtc_timer rtctimer;
52static struct rtc_device *rtcdev;
53static DEFINE_SPINLOCK(rtcdev_lock);
54
55/**
56 * alarmtimer_get_rtcdev - Return selected rtcdevice
57 *
58 * This function returns the rtc device to use for wakealarms.
59 * If one has not already been chosen, it checks to see if a
60 * functional rtc device is available.
61 */
62struct rtc_device *alarmtimer_get_rtcdev(void)
63{
64 unsigned long flags;
65 struct rtc_device *ret;
66
67 spin_lock_irqsave(&rtcdev_lock, flags);
68 ret = rtcdev;
69 spin_unlock_irqrestore(&rtcdev_lock, flags);
70
71 return ret;
72}
73
74
75static int alarmtimer_rtc_add_device(struct device *dev,
76 struct class_interface *class_intf)
77{
78 unsigned long flags;
79 struct rtc_device *rtc = to_rtc_device(dev);
80
81 if (rtcdev)
82 return -EBUSY;
83
84 if (!rtc->ops->set_alarm)
85 return -1;
86 if (!device_may_wakeup(rtc->dev.parent))
87 return -1;
88
89 spin_lock_irqsave(&rtcdev_lock, flags);
90 if (!rtcdev) {
91 rtcdev = rtc;
92 /* hold a reference so it doesn't go away */
93 get_device(dev);
94 }
95 spin_unlock_irqrestore(&rtcdev_lock, flags);
96 return 0;
97}
98
99static inline void alarmtimer_rtc_timer_init(void)
100{
101 rtc_timer_init(&rtctimer, NULL, NULL);
102}
103
104static struct class_interface alarmtimer_rtc_interface = {
105 .add_dev = &alarmtimer_rtc_add_device,
106};
107
108static int alarmtimer_rtc_interface_setup(void)
109{
110 alarmtimer_rtc_interface.class = rtc_class;
111 return class_interface_register(&alarmtimer_rtc_interface);
112}
113static void alarmtimer_rtc_interface_remove(void)
114{
115 class_interface_unregister(&alarmtimer_rtc_interface);
116}
117#else
118struct rtc_device *alarmtimer_get_rtcdev(void)
119{
120 return NULL;
121}
122#define rtcdev (NULL)
123static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
124static inline void alarmtimer_rtc_interface_remove(void) { }
125static inline void alarmtimer_rtc_timer_init(void) { }
126#endif
127
128/**
129 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
130 * @base: pointer to the base where the timer is being run
131 * @alarm: pointer to alarm being enqueued.
132 *
133 * Adds alarm to a alarm_base timerqueue and if necessary sets
134 * an hrtimer to run.
135 *
136 * Must hold base->lock when calling.
137 */
138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
139{
140 timerqueue_add(&base->timerqueue, &alarm->node);
141 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
142
143 if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
144 hrtimer_try_to_cancel(&base->timer);
145 hrtimer_start(&base->timer, alarm->node.expires,
146 HRTIMER_MODE_ABS);
147 }
148}
149
150/**
151 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
152 * @base: pointer to the base where the timer is running
153 * @alarm: pointer to alarm being removed
154 *
155 * Removes alarm to a alarm_base timerqueue and if necessary sets
156 * a new timer to run.
157 *
158 * Must hold base->lock when calling.
159 */
160static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
161{
162 struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
163
164 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
165 return;
166
167 timerqueue_del(&base->timerqueue, &alarm->node);
168 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
169
170 if (next == &alarm->node) {
171 hrtimer_try_to_cancel(&base->timer);
172 next = timerqueue_getnext(&base->timerqueue);
173 if (!next)
174 return;
175 hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
176 }
177}
178
179
180/**
181 * alarmtimer_fired - Handles alarm hrtimer being fired.
182 * @timer: pointer to hrtimer being run
183 *
184 * When a alarm timer fires, this runs through the timerqueue to
185 * see which alarms expired, and runs those. If there are more alarm
186 * timers queued for the future, we set the hrtimer to fire when
187 * when the next future alarm timer expires.
188 */
189static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
190{
191 struct alarm_base *base = container_of(timer, struct alarm_base, timer);
192 struct timerqueue_node *next;
193 unsigned long flags;
194 ktime_t now;
195 int ret = HRTIMER_NORESTART;
196 int restart = ALARMTIMER_NORESTART;
197
198 spin_lock_irqsave(&base->lock, flags);
199 now = base->gettime();
200 while ((next = timerqueue_getnext(&base->timerqueue))) {
201 struct alarm *alarm;
202 ktime_t expired = next->expires;
203
204 if (expired.tv64 > now.tv64)
205 break;
206
207 alarm = container_of(next, struct alarm, node);
208
209 timerqueue_del(&base->timerqueue, &alarm->node);
210 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
211
212 alarm->state |= ALARMTIMER_STATE_CALLBACK;
213 spin_unlock_irqrestore(&base->lock, flags);
214 if (alarm->function)
215 restart = alarm->function(alarm, now);
216 spin_lock_irqsave(&base->lock, flags);
217 alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
218
219 if (restart != ALARMTIMER_NORESTART) {
220 timerqueue_add(&base->timerqueue, &alarm->node);
221 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
222 }
223 }
224
225 if (next) {
226 hrtimer_set_expires(&base->timer, next->expires);
227 ret = HRTIMER_RESTART;
228 }
229 spin_unlock_irqrestore(&base->lock, flags);
230
231 return ret;
232
233}
234
235#ifdef CONFIG_RTC_CLASS
236/**
237 * alarmtimer_suspend - Suspend time callback
238 * @dev: unused
239 * @state: unused
240 *
241 * When we are going into suspend, we look through the bases
242 * to see which is the soonest timer to expire. We then
243 * set an rtc timer to fire that far into the future, which
244 * will wake us from suspend.
245 */
246static int alarmtimer_suspend(struct device *dev)
247{
248 struct rtc_time tm;
249 ktime_t min, now;
250 unsigned long flags;
251 struct rtc_device *rtc;
252 int i;
253
254 spin_lock_irqsave(&freezer_delta_lock, flags);
255 min = freezer_delta;
256 freezer_delta = ktime_set(0, 0);
257 spin_unlock_irqrestore(&freezer_delta_lock, flags);
258
259 rtc = alarmtimer_get_rtcdev();
260 /* If we have no rtcdev, just return */
261 if (!rtc)
262 return 0;
263
264 /* Find the soonest timer to expire*/
265 for (i = 0; i < ALARM_NUMTYPE; i++) {
266 struct alarm_base *base = &alarm_bases[i];
267 struct timerqueue_node *next;
268 ktime_t delta;
269
270 spin_lock_irqsave(&base->lock, flags);
271 next = timerqueue_getnext(&base->timerqueue);
272 spin_unlock_irqrestore(&base->lock, flags);
273 if (!next)
274 continue;
275 delta = ktime_sub(next->expires, base->gettime());
276 if (!min.tv64 || (delta.tv64 < min.tv64))
277 min = delta;
278 }
279 if (min.tv64 == 0)
280 return 0;
281
282 /* XXX - Should we enforce a minimum sleep time? */
283 WARN_ON(min.tv64 < NSEC_PER_SEC);
284
285 /* Setup an rtc timer to fire that far in the future */
286 rtc_timer_cancel(rtc, &rtctimer);
287 rtc_read_time(rtc, &tm);
288 now = rtc_tm_to_ktime(tm);
289 now = ktime_add(now, min);
290
291 rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
292
293 return 0;
294}
295#else
296static int alarmtimer_suspend(struct device *dev)
297{
298 return 0;
299}
300#endif
301
302static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
303{
304 ktime_t delta;
305 unsigned long flags;
306 struct alarm_base *base = &alarm_bases[type];
307
308 delta = ktime_sub(absexp, base->gettime());
309
310 spin_lock_irqsave(&freezer_delta_lock, flags);
311 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
312 freezer_delta = delta;
313 spin_unlock_irqrestore(&freezer_delta_lock, flags);
314}
315
316
317/**
318 * alarm_init - Initialize an alarm structure
319 * @alarm: ptr to alarm to be initialized
320 * @type: the type of the alarm
321 * @function: callback that is run when the alarm fires
322 */
323void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
324 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
325{
326 timerqueue_init(&alarm->node);
327 alarm->function = function;
328 alarm->type = type;
329 alarm->state = ALARMTIMER_STATE_INACTIVE;
330}
331
332/**
333 * alarm_start - Sets an alarm to fire
334 * @alarm: ptr to alarm to set
335 * @start: time to run the alarm
336 */
337void alarm_start(struct alarm *alarm, ktime_t start)
338{
339 struct alarm_base *base = &alarm_bases[alarm->type];
340 unsigned long flags;
341
342 spin_lock_irqsave(&base->lock, flags);
343 if (alarmtimer_active(alarm))
344 alarmtimer_remove(base, alarm);
345 alarm->node.expires = start;
346 alarmtimer_enqueue(base, alarm);
347 spin_unlock_irqrestore(&base->lock, flags);
348}
349
350/**
351 * alarm_try_to_cancel - Tries to cancel an alarm timer
352 * @alarm: ptr to alarm to be canceled
353 *
354 * Returns 1 if the timer was canceled, 0 if it was not running,
355 * and -1 if the callback was running
356 */
357int alarm_try_to_cancel(struct alarm *alarm)
358{
359 struct alarm_base *base = &alarm_bases[alarm->type];
360 unsigned long flags;
361 int ret = -1;
362 spin_lock_irqsave(&base->lock, flags);
363
364 if (alarmtimer_callback_running(alarm))
365 goto out;
366
367 if (alarmtimer_is_queued(alarm)) {
368 alarmtimer_remove(base, alarm);
369 ret = 1;
370 } else
371 ret = 0;
372out:
373 spin_unlock_irqrestore(&base->lock, flags);
374 return ret;
375}
376
377
378/**
379 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
380 * @alarm: ptr to alarm to be canceled
381 *
382 * Returns 1 if the timer was canceled, 0 if it was not active.
383 */
384int alarm_cancel(struct alarm *alarm)
385{
386 for (;;) {
387 int ret = alarm_try_to_cancel(alarm);
388 if (ret >= 0)
389 return ret;
390 cpu_relax();
391 }
392}
393
394
395u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
396{
397 u64 overrun = 1;
398 ktime_t delta;
399
400 delta = ktime_sub(now, alarm->node.expires);
401
402 if (delta.tv64 < 0)
403 return 0;
404
405 if (unlikely(delta.tv64 >= interval.tv64)) {
406 s64 incr = ktime_to_ns(interval);
407
408 overrun = ktime_divns(delta, incr);
409
410 alarm->node.expires = ktime_add_ns(alarm->node.expires,
411 incr*overrun);
412
413 if (alarm->node.expires.tv64 > now.tv64)
414 return overrun;
415 /*
416 * This (and the ktime_add() below) is the
417 * correction for exact:
418 */
419 overrun++;
420 }
421
422 alarm->node.expires = ktime_add(alarm->node.expires, interval);
423 return overrun;
424}
425
426
427
428
429/**
430 * clock2alarm - helper that converts from clockid to alarmtypes
431 * @clockid: clockid.
432 */
433static enum alarmtimer_type clock2alarm(clockid_t clockid)
434{
435 if (clockid == CLOCK_REALTIME_ALARM)
436 return ALARM_REALTIME;
437 if (clockid == CLOCK_BOOTTIME_ALARM)
438 return ALARM_BOOTTIME;
439 return -1;
440}
441
442/**
443 * alarm_handle_timer - Callback for posix timers
444 * @alarm: alarm that fired
445 *
446 * Posix timer callback for expired alarm timers.
447 */
448static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
449 ktime_t now)
450{
451 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
452 it.alarm.alarmtimer);
453 if (posix_timer_event(ptr, 0) != 0)
454 ptr->it_overrun++;
455
456 /* Re-add periodic timers */
457 if (ptr->it.alarm.interval.tv64) {
458 ptr->it_overrun += alarm_forward(alarm, now,
459 ptr->it.alarm.interval);
460 return ALARMTIMER_RESTART;
461 }
462 return ALARMTIMER_NORESTART;
463}
464
465/**
466 * alarm_clock_getres - posix getres interface
467 * @which_clock: clockid
468 * @tp: timespec to fill
469 *
470 * Returns the granularity of underlying alarm base clock
471 */
472static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
473{
474 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
475
476 if (!alarmtimer_get_rtcdev())
477 return -ENOTSUPP;
478
479 return hrtimer_get_res(baseid, tp);
480}
481
482/**
483 * alarm_clock_get - posix clock_get interface
484 * @which_clock: clockid
485 * @tp: timespec to fill.
486 *
487 * Provides the underlying alarm base time.
488 */
489static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
490{
491 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
492
493 if (!alarmtimer_get_rtcdev())
494 return -ENOTSUPP;
495
496 *tp = ktime_to_timespec(base->gettime());
497 return 0;
498}
499
500/**
501 * alarm_timer_create - posix timer_create interface
502 * @new_timer: k_itimer pointer to manage
503 *
504 * Initializes the k_itimer structure.
505 */
506static int alarm_timer_create(struct k_itimer *new_timer)
507{
508 enum alarmtimer_type type;
509 struct alarm_base *base;
510
511 if (!alarmtimer_get_rtcdev())
512 return -ENOTSUPP;
513
514 if (!capable(CAP_WAKE_ALARM))
515 return -EPERM;
516
517 type = clock2alarm(new_timer->it_clock);
518 base = &alarm_bases[type];
519 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
520 return 0;
521}
522
523/**
524 * alarm_timer_get - posix timer_get interface
525 * @new_timer: k_itimer pointer
526 * @cur_setting: itimerspec data to fill
527 *
528 * Copies the itimerspec data out from the k_itimer
529 */
530static void alarm_timer_get(struct k_itimer *timr,
531 struct itimerspec *cur_setting)
532{
533 memset(cur_setting, 0, sizeof(struct itimerspec));
534
535 cur_setting->it_interval =
536 ktime_to_timespec(timr->it.alarm.interval);
537 cur_setting->it_value =
538 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
539 return;
540}
541
542/**
543 * alarm_timer_del - posix timer_del interface
544 * @timr: k_itimer pointer to be deleted
545 *
546 * Cancels any programmed alarms for the given timer.
547 */
548static int alarm_timer_del(struct k_itimer *timr)
549{
550 if (!rtcdev)
551 return -ENOTSUPP;
552
553 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
554 return TIMER_RETRY;
555
556 return 0;
557}
558
559/**
560 * alarm_timer_set - posix timer_set interface
561 * @timr: k_itimer pointer to be deleted
562 * @flags: timer flags
563 * @new_setting: itimerspec to be used
564 * @old_setting: itimerspec being replaced
565 *
566 * Sets the timer to new_setting, and starts the timer.
567 */
568static int alarm_timer_set(struct k_itimer *timr, int flags,
569 struct itimerspec *new_setting,
570 struct itimerspec *old_setting)
571{
572 if (!rtcdev)
573 return -ENOTSUPP;
574
575 if (old_setting)
576 alarm_timer_get(timr, old_setting);
577
578 /* If the timer was already set, cancel it */
579 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
580 return TIMER_RETRY;
581
582 /* start the timer */
583 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
584 alarm_start(&timr->it.alarm.alarmtimer,
585 timespec_to_ktime(new_setting->it_value));
586 return 0;
587}
588
589/**
590 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
591 * @alarm: ptr to alarm that fired
592 *
593 * Wakes up the task that set the alarmtimer
594 */
595static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
596 ktime_t now)
597{
598 struct task_struct *task = (struct task_struct *)alarm->data;
599
600 alarm->data = NULL;
601 if (task)
602 wake_up_process(task);
603 return ALARMTIMER_NORESTART;
604}
605
606/**
607 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
608 * @alarm: ptr to alarmtimer
609 * @absexp: absolute expiration time
610 *
611 * Sets the alarm timer and sleeps until it is fired or interrupted.
612 */
613static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
614{
615 alarm->data = (void *)current;
616 do {
617 set_current_state(TASK_INTERRUPTIBLE);
618 alarm_start(alarm, absexp);
619 if (likely(alarm->data))
620 schedule();
621
622 alarm_cancel(alarm);
623 } while (alarm->data && !signal_pending(current));
624
625 __set_current_state(TASK_RUNNING);
626
627 return (alarm->data == NULL);
628}
629
630
631/**
632 * update_rmtp - Update remaining timespec value
633 * @exp: expiration time
634 * @type: timer type
635 * @rmtp: user pointer to remaining timepsec value
636 *
637 * Helper function that fills in rmtp value with time between
638 * now and the exp value
639 */
640static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
641 struct timespec __user *rmtp)
642{
643 struct timespec rmt;
644 ktime_t rem;
645
646 rem = ktime_sub(exp, alarm_bases[type].gettime());
647
648 if (rem.tv64 <= 0)
649 return 0;
650 rmt = ktime_to_timespec(rem);
651
652 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
653 return -EFAULT;
654
655 return 1;
656
657}
658
659/**
660 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
661 * @restart: ptr to restart block
662 *
663 * Handles restarted clock_nanosleep calls
664 */
665static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
666{
667 enum alarmtimer_type type = restart->nanosleep.clockid;
668 ktime_t exp;
669 struct timespec __user *rmtp;
670 struct alarm alarm;
671 int ret = 0;
672
673 exp.tv64 = restart->nanosleep.expires;
674 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
675
676 if (alarmtimer_do_nsleep(&alarm, exp))
677 goto out;
678
679 if (freezing(current))
680 alarmtimer_freezerset(exp, type);
681
682 rmtp = restart->nanosleep.rmtp;
683 if (rmtp) {
684 ret = update_rmtp(exp, type, rmtp);
685 if (ret <= 0)
686 goto out;
687 }
688
689
690 /* The other values in restart are already filled in */
691 ret = -ERESTART_RESTARTBLOCK;
692out:
693 return ret;
694}
695
696/**
697 * alarm_timer_nsleep - alarmtimer nanosleep
698 * @which_clock: clockid
699 * @flags: determins abstime or relative
700 * @tsreq: requested sleep time (abs or rel)
701 * @rmtp: remaining sleep time saved
702 *
703 * Handles clock_nanosleep calls against _ALARM clockids
704 */
705static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
706 struct timespec *tsreq, struct timespec __user *rmtp)
707{
708 enum alarmtimer_type type = clock2alarm(which_clock);
709 struct alarm alarm;
710 ktime_t exp;
711 int ret = 0;
712 struct restart_block *restart;
713
714 if (!alarmtimer_get_rtcdev())
715 return -ENOTSUPP;
716
717 if (!capable(CAP_WAKE_ALARM))
718 return -EPERM;
719
720 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
721
722 exp = timespec_to_ktime(*tsreq);
723 /* Convert (if necessary) to absolute time */
724 if (flags != TIMER_ABSTIME) {
725 ktime_t now = alarm_bases[type].gettime();
726 exp = ktime_add(now, exp);
727 }
728
729 if (alarmtimer_do_nsleep(&alarm, exp))
730 goto out;
731
732 if (freezing(current))
733 alarmtimer_freezerset(exp, type);
734
735 /* abs timers don't set remaining time or restart */
736 if (flags == TIMER_ABSTIME) {
737 ret = -ERESTARTNOHAND;
738 goto out;
739 }
740
741 if (rmtp) {
742 ret = update_rmtp(exp, type, rmtp);
743 if (ret <= 0)
744 goto out;
745 }
746
747 restart = ¤t_thread_info()->restart_block;
748 restart->fn = alarm_timer_nsleep_restart;
749 restart->nanosleep.clockid = type;
750 restart->nanosleep.expires = exp.tv64;
751 restart->nanosleep.rmtp = rmtp;
752 ret = -ERESTART_RESTARTBLOCK;
753
754out:
755 return ret;
756}
757
758
759/* Suspend hook structures */
760static const struct dev_pm_ops alarmtimer_pm_ops = {
761 .suspend = alarmtimer_suspend,
762};
763
764static struct platform_driver alarmtimer_driver = {
765 .driver = {
766 .name = "alarmtimer",
767 .pm = &alarmtimer_pm_ops,
768 }
769};
770
771/**
772 * alarmtimer_init - Initialize alarm timer code
773 *
774 * This function initializes the alarm bases and registers
775 * the posix clock ids.
776 */
777static int __init alarmtimer_init(void)
778{
779 struct platform_device *pdev;
780 int error = 0;
781 int i;
782 struct k_clock alarm_clock = {
783 .clock_getres = alarm_clock_getres,
784 .clock_get = alarm_clock_get,
785 .timer_create = alarm_timer_create,
786 .timer_set = alarm_timer_set,
787 .timer_del = alarm_timer_del,
788 .timer_get = alarm_timer_get,
789 .nsleep = alarm_timer_nsleep,
790 };
791
792 alarmtimer_rtc_timer_init();
793
794 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
795 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
796
797 /* Initialize alarm bases */
798 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
799 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
800 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
801 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
802 for (i = 0; i < ALARM_NUMTYPE; i++) {
803 timerqueue_init_head(&alarm_bases[i].timerqueue);
804 spin_lock_init(&alarm_bases[i].lock);
805 hrtimer_init(&alarm_bases[i].timer,
806 alarm_bases[i].base_clockid,
807 HRTIMER_MODE_ABS);
808 alarm_bases[i].timer.function = alarmtimer_fired;
809 }
810
811 error = alarmtimer_rtc_interface_setup();
812 if (error)
813 return error;
814
815 error = platform_driver_register(&alarmtimer_driver);
816 if (error)
817 goto out_if;
818
819 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
820 if (IS_ERR(pdev)) {
821 error = PTR_ERR(pdev);
822 goto out_drv;
823 }
824 return 0;
825
826out_drv:
827 platform_driver_unregister(&alarmtimer_driver);
828out_if:
829 alarmtimer_rtc_interface_remove();
830 return error;
831}
832device_initcall(alarmtimer_init);
1/*
2 * Alarmtimer interface
3 *
4 * This interface provides a timer which is similarto hrtimers,
5 * but triggers a RTC alarm if the box is suspend.
6 *
7 * This interface is influenced by the Android RTC Alarm timer
8 * interface.
9 *
10 * Copyright (C) 2010 IBM Corperation
11 *
12 * Author: John Stultz <john.stultz@linaro.org>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 */
18#include <linux/time.h>
19#include <linux/hrtimer.h>
20#include <linux/timerqueue.h>
21#include <linux/rtc.h>
22#include <linux/alarmtimer.h>
23#include <linux/mutex.h>
24#include <linux/platform_device.h>
25#include <linux/posix-timers.h>
26#include <linux/workqueue.h>
27#include <linux/freezer.h>
28
29/**
30 * struct alarm_base - Alarm timer bases
31 * @lock: Lock for syncrhonized access to the base
32 * @timerqueue: Timerqueue head managing the list of events
33 * @timer: hrtimer used to schedule events while running
34 * @gettime: Function to read the time correlating to the base
35 * @base_clockid: clockid for the base
36 */
37static struct alarm_base {
38 spinlock_t lock;
39 struct timerqueue_head timerqueue;
40 struct hrtimer timer;
41 ktime_t (*gettime)(void);
42 clockid_t base_clockid;
43} alarm_bases[ALARM_NUMTYPE];
44
45/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
46static ktime_t freezer_delta;
47static DEFINE_SPINLOCK(freezer_delta_lock);
48
49#ifdef CONFIG_RTC_CLASS
50/* rtc timer and device for setting alarm wakeups at suspend */
51static struct rtc_timer rtctimer;
52static struct rtc_device *rtcdev;
53static DEFINE_SPINLOCK(rtcdev_lock);
54
55/**
56 * has_wakealarm - check rtc device has wakealarm ability
57 * @dev: current device
58 * @name_ptr: name to be returned
59 *
60 * This helper function checks to see if the rtc device can wake
61 * from suspend.
62 */
63static int has_wakealarm(struct device *dev, void *name_ptr)
64{
65 struct rtc_device *candidate = to_rtc_device(dev);
66
67 if (!candidate->ops->set_alarm)
68 return 0;
69 if (!device_may_wakeup(candidate->dev.parent))
70 return 0;
71
72 *(const char **)name_ptr = dev_name(dev);
73 return 1;
74}
75
76/**
77 * alarmtimer_get_rtcdev - Return selected rtcdevice
78 *
79 * This function returns the rtc device to use for wakealarms.
80 * If one has not already been chosen, it checks to see if a
81 * functional rtc device is available.
82 */
83static struct rtc_device *alarmtimer_get_rtcdev(void)
84{
85 struct device *dev;
86 char *str;
87 unsigned long flags;
88 struct rtc_device *ret;
89
90 spin_lock_irqsave(&rtcdev_lock, flags);
91 if (!rtcdev) {
92 /* Find an rtc device and init the rtc_timer */
93 dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
94 /* If we have a device then str is valid. See has_wakealarm() */
95 if (dev) {
96 rtcdev = rtc_class_open(str);
97 /*
98 * Drop the reference we got in class_find_device,
99 * rtc_open takes its own.
100 */
101 put_device(dev);
102 rtc_timer_init(&rtctimer, NULL, NULL);
103 }
104 }
105 ret = rtcdev;
106 spin_unlock_irqrestore(&rtcdev_lock, flags);
107
108 return ret;
109}
110#else
111#define alarmtimer_get_rtcdev() (0)
112#define rtcdev (0)
113#endif
114
115
116/**
117 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
118 * @base: pointer to the base where the timer is being run
119 * @alarm: pointer to alarm being enqueued.
120 *
121 * Adds alarm to a alarm_base timerqueue and if necessary sets
122 * an hrtimer to run.
123 *
124 * Must hold base->lock when calling.
125 */
126static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
127{
128 timerqueue_add(&base->timerqueue, &alarm->node);
129 if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
130 hrtimer_try_to_cancel(&base->timer);
131 hrtimer_start(&base->timer, alarm->node.expires,
132 HRTIMER_MODE_ABS);
133 }
134}
135
136/**
137 * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
138 * @base: pointer to the base where the timer is running
139 * @alarm: pointer to alarm being removed
140 *
141 * Removes alarm to a alarm_base timerqueue and if necessary sets
142 * a new timer to run.
143 *
144 * Must hold base->lock when calling.
145 */
146static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
147{
148 struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
149
150 timerqueue_del(&base->timerqueue, &alarm->node);
151 if (next == &alarm->node) {
152 hrtimer_try_to_cancel(&base->timer);
153 next = timerqueue_getnext(&base->timerqueue);
154 if (!next)
155 return;
156 hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
157 }
158}
159
160
161/**
162 * alarmtimer_fired - Handles alarm hrtimer being fired.
163 * @timer: pointer to hrtimer being run
164 *
165 * When a alarm timer fires, this runs through the timerqueue to
166 * see which alarms expired, and runs those. If there are more alarm
167 * timers queued for the future, we set the hrtimer to fire when
168 * when the next future alarm timer expires.
169 */
170static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
171{
172 struct alarm_base *base = container_of(timer, struct alarm_base, timer);
173 struct timerqueue_node *next;
174 unsigned long flags;
175 ktime_t now;
176 int ret = HRTIMER_NORESTART;
177
178 spin_lock_irqsave(&base->lock, flags);
179 now = base->gettime();
180 while ((next = timerqueue_getnext(&base->timerqueue))) {
181 struct alarm *alarm;
182 ktime_t expired = next->expires;
183
184 if (expired.tv64 >= now.tv64)
185 break;
186
187 alarm = container_of(next, struct alarm, node);
188
189 timerqueue_del(&base->timerqueue, &alarm->node);
190 alarm->enabled = 0;
191 /* Re-add periodic timers */
192 if (alarm->period.tv64) {
193 alarm->node.expires = ktime_add(expired, alarm->period);
194 timerqueue_add(&base->timerqueue, &alarm->node);
195 alarm->enabled = 1;
196 }
197 spin_unlock_irqrestore(&base->lock, flags);
198 if (alarm->function)
199 alarm->function(alarm);
200 spin_lock_irqsave(&base->lock, flags);
201 }
202
203 if (next) {
204 hrtimer_set_expires(&base->timer, next->expires);
205 ret = HRTIMER_RESTART;
206 }
207 spin_unlock_irqrestore(&base->lock, flags);
208
209 return ret;
210
211}
212
213#ifdef CONFIG_RTC_CLASS
214/**
215 * alarmtimer_suspend - Suspend time callback
216 * @dev: unused
217 * @state: unused
218 *
219 * When we are going into suspend, we look through the bases
220 * to see which is the soonest timer to expire. We then
221 * set an rtc timer to fire that far into the future, which
222 * will wake us from suspend.
223 */
224static int alarmtimer_suspend(struct device *dev)
225{
226 struct rtc_time tm;
227 ktime_t min, now;
228 unsigned long flags;
229 struct rtc_device *rtc;
230 int i;
231
232 spin_lock_irqsave(&freezer_delta_lock, flags);
233 min = freezer_delta;
234 freezer_delta = ktime_set(0, 0);
235 spin_unlock_irqrestore(&freezer_delta_lock, flags);
236
237 rtc = rtcdev;
238 /* If we have no rtcdev, just return */
239 if (!rtc)
240 return 0;
241
242 /* Find the soonest timer to expire*/
243 for (i = 0; i < ALARM_NUMTYPE; i++) {
244 struct alarm_base *base = &alarm_bases[i];
245 struct timerqueue_node *next;
246 ktime_t delta;
247
248 spin_lock_irqsave(&base->lock, flags);
249 next = timerqueue_getnext(&base->timerqueue);
250 spin_unlock_irqrestore(&base->lock, flags);
251 if (!next)
252 continue;
253 delta = ktime_sub(next->expires, base->gettime());
254 if (!min.tv64 || (delta.tv64 < min.tv64))
255 min = delta;
256 }
257 if (min.tv64 == 0)
258 return 0;
259
260 /* XXX - Should we enforce a minimum sleep time? */
261 WARN_ON(min.tv64 < NSEC_PER_SEC);
262
263 /* Setup an rtc timer to fire that far in the future */
264 rtc_timer_cancel(rtc, &rtctimer);
265 rtc_read_time(rtc, &tm);
266 now = rtc_tm_to_ktime(tm);
267 now = ktime_add(now, min);
268
269 rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
270
271 return 0;
272}
273#else
274static int alarmtimer_suspend(struct device *dev)
275{
276 return 0;
277}
278#endif
279
280static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
281{
282 ktime_t delta;
283 unsigned long flags;
284 struct alarm_base *base = &alarm_bases[type];
285
286 delta = ktime_sub(absexp, base->gettime());
287
288 spin_lock_irqsave(&freezer_delta_lock, flags);
289 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
290 freezer_delta = delta;
291 spin_unlock_irqrestore(&freezer_delta_lock, flags);
292}
293
294
295/**
296 * alarm_init - Initialize an alarm structure
297 * @alarm: ptr to alarm to be initialized
298 * @type: the type of the alarm
299 * @function: callback that is run when the alarm fires
300 */
301void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
302 void (*function)(struct alarm *))
303{
304 timerqueue_init(&alarm->node);
305 alarm->period = ktime_set(0, 0);
306 alarm->function = function;
307 alarm->type = type;
308 alarm->enabled = 0;
309}
310
311/**
312 * alarm_start - Sets an alarm to fire
313 * @alarm: ptr to alarm to set
314 * @start: time to run the alarm
315 * @period: period at which the alarm will recur
316 */
317void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
318{
319 struct alarm_base *base = &alarm_bases[alarm->type];
320 unsigned long flags;
321
322 spin_lock_irqsave(&base->lock, flags);
323 if (alarm->enabled)
324 alarmtimer_remove(base, alarm);
325 alarm->node.expires = start;
326 alarm->period = period;
327 alarmtimer_enqueue(base, alarm);
328 alarm->enabled = 1;
329 spin_unlock_irqrestore(&base->lock, flags);
330}
331
332/**
333 * alarm_cancel - Tries to cancel an alarm timer
334 * @alarm: ptr to alarm to be canceled
335 */
336void alarm_cancel(struct alarm *alarm)
337{
338 struct alarm_base *base = &alarm_bases[alarm->type];
339 unsigned long flags;
340
341 spin_lock_irqsave(&base->lock, flags);
342 if (alarm->enabled)
343 alarmtimer_remove(base, alarm);
344 alarm->enabled = 0;
345 spin_unlock_irqrestore(&base->lock, flags);
346}
347
348
349/**
350 * clock2alarm - helper that converts from clockid to alarmtypes
351 * @clockid: clockid.
352 */
353static enum alarmtimer_type clock2alarm(clockid_t clockid)
354{
355 if (clockid == CLOCK_REALTIME_ALARM)
356 return ALARM_REALTIME;
357 if (clockid == CLOCK_BOOTTIME_ALARM)
358 return ALARM_BOOTTIME;
359 return -1;
360}
361
362/**
363 * alarm_handle_timer - Callback for posix timers
364 * @alarm: alarm that fired
365 *
366 * Posix timer callback for expired alarm timers.
367 */
368static void alarm_handle_timer(struct alarm *alarm)
369{
370 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
371 it.alarmtimer);
372 if (posix_timer_event(ptr, 0) != 0)
373 ptr->it_overrun++;
374}
375
376/**
377 * alarm_clock_getres - posix getres interface
378 * @which_clock: clockid
379 * @tp: timespec to fill
380 *
381 * Returns the granularity of underlying alarm base clock
382 */
383static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
384{
385 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
386
387 if (!alarmtimer_get_rtcdev())
388 return -ENOTSUPP;
389
390 return hrtimer_get_res(baseid, tp);
391}
392
393/**
394 * alarm_clock_get - posix clock_get interface
395 * @which_clock: clockid
396 * @tp: timespec to fill.
397 *
398 * Provides the underlying alarm base time.
399 */
400static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
401{
402 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
403
404 if (!alarmtimer_get_rtcdev())
405 return -ENOTSUPP;
406
407 *tp = ktime_to_timespec(base->gettime());
408 return 0;
409}
410
411/**
412 * alarm_timer_create - posix timer_create interface
413 * @new_timer: k_itimer pointer to manage
414 *
415 * Initializes the k_itimer structure.
416 */
417static int alarm_timer_create(struct k_itimer *new_timer)
418{
419 enum alarmtimer_type type;
420 struct alarm_base *base;
421
422 if (!alarmtimer_get_rtcdev())
423 return -ENOTSUPP;
424
425 if (!capable(CAP_WAKE_ALARM))
426 return -EPERM;
427
428 type = clock2alarm(new_timer->it_clock);
429 base = &alarm_bases[type];
430 alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer);
431 return 0;
432}
433
434/**
435 * alarm_timer_get - posix timer_get interface
436 * @new_timer: k_itimer pointer
437 * @cur_setting: itimerspec data to fill
438 *
439 * Copies the itimerspec data out from the k_itimer
440 */
441static void alarm_timer_get(struct k_itimer *timr,
442 struct itimerspec *cur_setting)
443{
444 memset(cur_setting, 0, sizeof(struct itimerspec));
445
446 cur_setting->it_interval =
447 ktime_to_timespec(timr->it.alarmtimer.period);
448 cur_setting->it_value =
449 ktime_to_timespec(timr->it.alarmtimer.node.expires);
450 return;
451}
452
453/**
454 * alarm_timer_del - posix timer_del interface
455 * @timr: k_itimer pointer to be deleted
456 *
457 * Cancels any programmed alarms for the given timer.
458 */
459static int alarm_timer_del(struct k_itimer *timr)
460{
461 if (!rtcdev)
462 return -ENOTSUPP;
463
464 alarm_cancel(&timr->it.alarmtimer);
465 return 0;
466}
467
468/**
469 * alarm_timer_set - posix timer_set interface
470 * @timr: k_itimer pointer to be deleted
471 * @flags: timer flags
472 * @new_setting: itimerspec to be used
473 * @old_setting: itimerspec being replaced
474 *
475 * Sets the timer to new_setting, and starts the timer.
476 */
477static int alarm_timer_set(struct k_itimer *timr, int flags,
478 struct itimerspec *new_setting,
479 struct itimerspec *old_setting)
480{
481 if (!rtcdev)
482 return -ENOTSUPP;
483
484 /*
485 * XXX HACK! Currently we can DOS a system if the interval
486 * period on alarmtimers is too small. Cap the interval here
487 * to 100us and solve this properly in a future patch! -jstultz
488 */
489 if ((new_setting->it_interval.tv_sec == 0) &&
490 (new_setting->it_interval.tv_nsec < 100000))
491 new_setting->it_interval.tv_nsec = 100000;
492
493 if (old_setting)
494 alarm_timer_get(timr, old_setting);
495
496 /* If the timer was already set, cancel it */
497 alarm_cancel(&timr->it.alarmtimer);
498
499 /* start the timer */
500 alarm_start(&timr->it.alarmtimer,
501 timespec_to_ktime(new_setting->it_value),
502 timespec_to_ktime(new_setting->it_interval));
503 return 0;
504}
505
506/**
507 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
508 * @alarm: ptr to alarm that fired
509 *
510 * Wakes up the task that set the alarmtimer
511 */
512static void alarmtimer_nsleep_wakeup(struct alarm *alarm)
513{
514 struct task_struct *task = (struct task_struct *)alarm->data;
515
516 alarm->data = NULL;
517 if (task)
518 wake_up_process(task);
519}
520
521/**
522 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
523 * @alarm: ptr to alarmtimer
524 * @absexp: absolute expiration time
525 *
526 * Sets the alarm timer and sleeps until it is fired or interrupted.
527 */
528static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
529{
530 alarm->data = (void *)current;
531 do {
532 set_current_state(TASK_INTERRUPTIBLE);
533 alarm_start(alarm, absexp, ktime_set(0, 0));
534 if (likely(alarm->data))
535 schedule();
536
537 alarm_cancel(alarm);
538 } while (alarm->data && !signal_pending(current));
539
540 __set_current_state(TASK_RUNNING);
541
542 return (alarm->data == NULL);
543}
544
545
546/**
547 * update_rmtp - Update remaining timespec value
548 * @exp: expiration time
549 * @type: timer type
550 * @rmtp: user pointer to remaining timepsec value
551 *
552 * Helper function that fills in rmtp value with time between
553 * now and the exp value
554 */
555static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
556 struct timespec __user *rmtp)
557{
558 struct timespec rmt;
559 ktime_t rem;
560
561 rem = ktime_sub(exp, alarm_bases[type].gettime());
562
563 if (rem.tv64 <= 0)
564 return 0;
565 rmt = ktime_to_timespec(rem);
566
567 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
568 return -EFAULT;
569
570 return 1;
571
572}
573
574/**
575 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
576 * @restart: ptr to restart block
577 *
578 * Handles restarted clock_nanosleep calls
579 */
580static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
581{
582 enum alarmtimer_type type = restart->nanosleep.clockid;
583 ktime_t exp;
584 struct timespec __user *rmtp;
585 struct alarm alarm;
586 int ret = 0;
587
588 exp.tv64 = restart->nanosleep.expires;
589 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
590
591 if (alarmtimer_do_nsleep(&alarm, exp))
592 goto out;
593
594 if (freezing(current))
595 alarmtimer_freezerset(exp, type);
596
597 rmtp = restart->nanosleep.rmtp;
598 if (rmtp) {
599 ret = update_rmtp(exp, type, rmtp);
600 if (ret <= 0)
601 goto out;
602 }
603
604
605 /* The other values in restart are already filled in */
606 ret = -ERESTART_RESTARTBLOCK;
607out:
608 return ret;
609}
610
611/**
612 * alarm_timer_nsleep - alarmtimer nanosleep
613 * @which_clock: clockid
614 * @flags: determins abstime or relative
615 * @tsreq: requested sleep time (abs or rel)
616 * @rmtp: remaining sleep time saved
617 *
618 * Handles clock_nanosleep calls against _ALARM clockids
619 */
620static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
621 struct timespec *tsreq, struct timespec __user *rmtp)
622{
623 enum alarmtimer_type type = clock2alarm(which_clock);
624 struct alarm alarm;
625 ktime_t exp;
626 int ret = 0;
627 struct restart_block *restart;
628
629 if (!alarmtimer_get_rtcdev())
630 return -ENOTSUPP;
631
632 if (!capable(CAP_WAKE_ALARM))
633 return -EPERM;
634
635 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
636
637 exp = timespec_to_ktime(*tsreq);
638 /* Convert (if necessary) to absolute time */
639 if (flags != TIMER_ABSTIME) {
640 ktime_t now = alarm_bases[type].gettime();
641 exp = ktime_add(now, exp);
642 }
643
644 if (alarmtimer_do_nsleep(&alarm, exp))
645 goto out;
646
647 if (freezing(current))
648 alarmtimer_freezerset(exp, type);
649
650 /* abs timers don't set remaining time or restart */
651 if (flags == TIMER_ABSTIME) {
652 ret = -ERESTARTNOHAND;
653 goto out;
654 }
655
656 if (rmtp) {
657 ret = update_rmtp(exp, type, rmtp);
658 if (ret <= 0)
659 goto out;
660 }
661
662 restart = ¤t_thread_info()->restart_block;
663 restart->fn = alarm_timer_nsleep_restart;
664 restart->nanosleep.clockid = type;
665 restart->nanosleep.expires = exp.tv64;
666 restart->nanosleep.rmtp = rmtp;
667 ret = -ERESTART_RESTARTBLOCK;
668
669out:
670 return ret;
671}
672
673
674/* Suspend hook structures */
675static const struct dev_pm_ops alarmtimer_pm_ops = {
676 .suspend = alarmtimer_suspend,
677};
678
679static struct platform_driver alarmtimer_driver = {
680 .driver = {
681 .name = "alarmtimer",
682 .pm = &alarmtimer_pm_ops,
683 }
684};
685
686/**
687 * alarmtimer_init - Initialize alarm timer code
688 *
689 * This function initializes the alarm bases and registers
690 * the posix clock ids.
691 */
692static int __init alarmtimer_init(void)
693{
694 int error = 0;
695 int i;
696 struct k_clock alarm_clock = {
697 .clock_getres = alarm_clock_getres,
698 .clock_get = alarm_clock_get,
699 .timer_create = alarm_timer_create,
700 .timer_set = alarm_timer_set,
701 .timer_del = alarm_timer_del,
702 .timer_get = alarm_timer_get,
703 .nsleep = alarm_timer_nsleep,
704 };
705
706 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
707 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
708
709 /* Initialize alarm bases */
710 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
711 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
712 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
713 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
714 for (i = 0; i < ALARM_NUMTYPE; i++) {
715 timerqueue_init_head(&alarm_bases[i].timerqueue);
716 spin_lock_init(&alarm_bases[i].lock);
717 hrtimer_init(&alarm_bases[i].timer,
718 alarm_bases[i].base_clockid,
719 HRTIMER_MODE_ABS);
720 alarm_bases[i].timer.function = alarmtimer_fired;
721 }
722 error = platform_driver_register(&alarmtimer_driver);
723 platform_device_register_simple("alarmtimer", -1, NULL, 0);
724
725 return error;
726}
727device_initcall(alarmtimer_init);
728